<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
         /*1. 手动去减 */
         /* width 160px */
         /* height 160px  */
         /* 2.css盒子模型 box-sizing: border-box*/
         width: 200px;
         height: 200px;
         background-color: pink;
         border: 10px solid red;
         padding: 10px;
         box-sizing: border-box;
        }
        
    </style>
</head>
<body>
    <div class="box">qwe</div>
</body>
</html>